Erythromycin prevents potentially harmful exudate from invading the tear ducts of the infant's eyes, leading to dry eyes.

Erythromycin ophthalmic ointment destroys an infectious exudate caused by Staphylococcus that could make the infant blind.

This ointment prevents the infant's eyelids from sticking together and helps the infant see.

This ophthalmic ointment prevents gonorrheal infection of the infant's eyes, potentially acquired from the birth canal.